Operation of internal-combustion engines



Patented Jan. 2, i946 OPERATION OF INTERNAL-COMBUSTION ENGINES Clyde 0.Davis, Woodbury, N. J., assignor to E. I. du Pont de Nemours & Company,Wilmington, Del., a corporation of Delaware No Drawing.

Application July 8, 1941,

Serial No. 401,547

V 2 Claims.

This invention relates to a novel method for the production andutilization of energy and more particularly to a method for theoperation of internal combustion engines.

Internal combustion engines are highly efficient sources of mechanicalpower and can be broadly divided into two classes, those in which boththe fuel and oxidant are introduced into the combustion chamber invaporous form and those into which the fuel is injected in finelydivided but non-vaporous form, because of the practical difliculties invaporizing the fuel. The two foregoing types are represented by theordinary gasoline engine and the Diesel engine, respectively. With suchengines, the oxygen of the air serves for the combustion of the fuel,since air is generally available free, uncompressed. In ceitain cases,however, internal combustion engines are operated in places where thereis a deficiency of available air or oxygen, or where at least the supplyis limited. Such conditions would hold, for example, in stratosphereflights and on board submarines, and the maintenance at hand of areservoir of highly combustible fuel might also be undesirable at times,as in wartime use under conditions of exposure to shell fire.

The object of the present invention is a novel method of producing andutilizing energy by use of an internal combustion engine. A furtherobject is a method for the operation of internal combustion engineswhich does not require an extensive supply of gaseous oxidizing agentsfor the combustion of the fuel. A still further object is a method forthe operation of internal combustion engines wherein both fuel andoxidizing agent are introduced in solution form, Additional objects willbe disclosed as the invention is described more in detail hereinafter.

I have found that the foregoing objects are obtained when I introduceinto the combustion chamber of an internal combustion engine a solutioncomprising ammonium nitrate and an oxidizable material and bring aboutthe combustion of the oxidizable material therein. Several types ofsolutions may be employed according to the invention. I may, forexample, dissolve ammonium nitrate in liquid ammonia and use such asolution, the ammonia being burnt in the available oxygen of theammonium nitrate. Alternatively, I may employ an aqueous solution ofammonium nitrate, said solution containing also a dissolved combustiblematerial. While such solutions are the ones that will preferably beemployed, my invention contemplates the use of any ammonium nitratesolution, whatever the solvent, where an oxidizable material is presenteither as solvent or as an additional solute. It will be apparent thatadditional oxidizing agents may be present also, along with the ammoniumnitrate.

Since the dissolved ammonium nitrate is a very considerable part of thecombustion'mixture and since other dissolved solids may be present also,it will be apparent that the most suitable type of internal combustionengine for use will be one in which the solution is injected in finelydivided form. It will be applicable, for example, in the Diesel enginetype, whether of the simple compression type or the semi-Diesel typewhere spark ignition is employed.

While ammonium nitrate is the principal oxidizing agent present, and isparticularly desirable because no solid residue remains aftercombustion, additional oxidants may be used also, such as solublechromates or dichromates, permanganates, alkali nitrates or nitrites,and the like. Such materials as nitrous oxide may be present also,either in liquid or in vaporous form.

Likewise, the combustible material may vary widely, either as solventfor the amonium nitrate or as additional dissolved material. One of mypreferred materials is anhydrous liquid ammonia which is a solvent forammonium nitrate, forming the so-called Diver's solution. Methyl andethyl alcohols may likewise be employed as a portion of the solution,mixed with liquid ammonia, if desired. Additional solvents capable ofapplication, as the entire solvent or portion thereof, are pyridine,acetone, formamide, dimethylformamide, and the like, The combustible mayalso be a dissolved material, especially when aqueous solutions ofammonium nitrate are used. The dissolved material may consist of suchsubstances as sugar, urea, diphenylamine, and many others. I

It will be understood that various additional materials, whichesentially are neither oxidants nor combustible materials, may bedesirable additions under certain conditions, as combustion accelerantsor retardants. knock suppressants, ignition point depressants, and thelike.

Various blends of combustible and oxidizing agent were appliedsuccessfully in a 4-cycle vertical type Diesel engine. These included a91-19 solution, by weight, of ammonium nitrate in liquid ammonia, an -20ammonium nitrateammonia mixture blended with methyl alcohol in variousproportions, a 50-50 blend of dimethylformamide and the vforegoingDiver's solution.

together with a small amount or ethyl nitrate, ammonium nitratedissolved in dimethyltormamide in a 30-70 ratio, and others.

The present invention is applicable to internal combustion enginesgenerally. It will be understood that this includes not only thoseengines which employ the reciprocating motion of pis tons, as in theDiesel engine, but also the gas tun-bine type of engine, in which rotarymotion and -impel1er vanes are used. I intend the invention to cover theprocess described when applied to any motor in which the fuel is burntin the combustion chamber thereof with utilization of the combustiongases.

The invention has been described in its essentials in the foregoing. Itwill be understood, however, that various departures may be made fromthe details of compositions and operation without going outside thescope of the invention. I intend to be limited therefore only by thefollowing patent claims.

I claim:

1. The method of producing and utilizing energy, which comprisesintroducing into the combustion chamber of an internal combustion enginea solution of ammonium nitrate in liquid ammonia and effecting thereinthe explosive combustion of said ammonia. v

2. A fuel for internal combustion engines comprising ammonium nitratedissolved in liquid ammonia.

CLYDE 0. DAVIS.

